Due to the enactment of various safety laws, persons working at elevated positions, for example, broadcast radio-frequency (RF) antennas or towers, are required to be protected against falls. The antennas commonly extend approximately 20-200 feet high and are typically mounted at the top of a tower, building or similar structure that can extend an additional 100-1500 feet high. Commonly, radiation emanates 360° from around the antenna's aperture and can radiate RF waves at powers ranging from approximately 10 kW to approximately 500 kW depending on the area to be covered.
Antenna installations like the one described above oftentimes employ fall prevention systems and/or attachment anchoring mechanisms that are connected to, or part of, the antenna. Typically, these fall prevention systems or attachment mechanisms typically utilize ropes or cables, referred to as rope grabs, to which a worker may anchor him or herself when installing, servicing, maintaining or sealing the antenna and or obstruction lights mounted on the antenna.
The rope or cables currently used in rope grabs are typically constructed from metal materials such as stainless steel, galvanized steel, aluminum and the like. Alternatively, other types of ropes currently used in fall prevention systems are constructed from synthetic materials such as nylon, polypropylene, Keviar® and the like.
The above-described ropes currently used in fall prevention systems have drawbacks however. For example, the synthetic ropes can be susceptible to the environment in which the antenna is located compromising the ropes' lifespan. Also, the synthetic materials from which the ropes are manufactured oftentimes do not resist ultraviolet (UV) rays or the RF radiation to which they are exposed, causing the ropes to break down or deteriorate over time. In addition, these synthetic ropes are also susceptible to the infiltration of water from the environment which also can lead to deterioration. Consequently, frequent maintenance and/or replacement of the ropes is sometimes required. Moreover, these ropes can be very expensive to manufacture or purchase. Thus, fall prevention systems currently employed in the art using synthetic materials may require frequent, costly maintenance. Additionally, with the absorption of water the material's dielectric constant is increased.
The ropes, or cables constructed from metal materials typically do not suffer from the above-described drawbacks associated with the use of synthetic ropes, however the metallic construction does have drawbacks. As previously described, an RF antenna typically emits a 360° radiation pattern. Metallic ropes will reflect the RF waves back to the antenna, causing a distortion of the radiation pattern. A metallic cable that is ungrounded can develop an electrical potential different from that of the antenna structure. This electrical potential can cause an are between the antenna structure and the cable. This will cause interference in the RF signal as well as destroy the cable.
Accordingly, there is a need in the art to provide a fall protection apparatus and method that is resistant to the environment in which it is deployed, reducing the amount of maintenance required for operation. Moreover, there is an additional need for a low maintenance fall protection system that is affordable. Further, there is a need for such an apparatus and method that minimizes distortion of the antenna's radiation pattern.